There is no natural method proven to guarantee a boy, but one medical technology comes close: IVF with genetic testing can identify male embryos with roughly 98% accuracy before transfer. For couples not pursuing fertility treatment, several popular natural approaches exist, though the scientific evidence behind them is mixed at best. Here’s what actually works, what might help, and what the science says about each option.
The Only Near-Guarantee: IVF With Genetic Testing
Preimplantation genetic testing (PGT-A) screens embryos created through IVF for chromosomal abnormalities and, in the process, identifies the sex of each embryo. The test is accurate up to 98% of the time. Your fertility team can then transfer only male embryos, making this the most reliable method of sex selection available.
The cost is significant. In the United States, a full IVF cycle with sex selection typically runs $25,000 to $35,000 at most clinics, though some lower-cost clinics offer it for $10,000 to $12,000 depending on the treatment plan and number of embryos tested. This involves the full IVF process: hormone injections, egg retrieval, fertilization in a lab, embryo biopsy, and frozen embryo transfer. For women under 35 using PGT-A, pregnancy rates per transfer hover around 56.5%, and cumulative success across three frozen transfers reaches about 95%.
It’s worth knowing that elective sex selection through IVF is legal in the United States and is not restricted to medical reasons. That is not the case everywhere. Australia banned non-medical sex selection in 2004. India prohibits all technologies used for sex selection. Canada and New Zealand also restrict reproductive sex selection to cases involving genetic disorders. If you’re outside the U.S., check your country’s specific regulations before pursuing this route.
Sperm Sorting: A Less Invasive Lab Option
A technology called MicroSort separates sperm carrying the Y chromosome (which produces boys) from those carrying the X chromosome. It works by using a laser to detect slight differences in DNA content between the two types. For male selection, the sorted sample (called YSort) yielded 81.5% boys among babies born in clinical trials. That’s lower than the 92% accuracy for selecting girls, because Y-bearing sperm carry slightly less DNA, making them harder to isolate cleanly.
MicroSort was developed under an FDA clinical trial in the U.S. but never received full approval, so it’s primarily available at international clinics. The sorted sperm can be used with intrauterine insemination (IUI), which is far less invasive and less expensive than IVF, or combined with IVF for higher pregnancy rates.
The Shettles Method: Timing Intercourse
The most well-known natural approach is the Shettles method, developed by Dr. Landrum Shettles in the 1960s. The idea is straightforward: Y-bearing sperm (boy-producing) are thought to swim faster but die sooner, while X-bearing sperm (girl-producing) are slower but hardier. To conceive a boy, Shettles recommended having intercourse as close to ovulation as possible, giving the faster Y sperm an advantage in reaching the egg first.
Shettles himself reported an 80% success rate for couples trying for boys. And a large 1979 study in The New England Journal of Medicine, covering over 3,000 births, did find that male babies were more often produced when intercourse happened closest to ovulation. That’s consistent with the theory.
But the picture gets muddier from there. A 1991 study found the opposite result: significantly fewer boys when conception occurred around ovulation. Then a 1995 New England Journal of Medicine study concluded there was no association at all between intercourse timing and the baby’s sex. Lab research does show real biological differences between X and Y sperm. Y sperm are more vulnerable to stress and die off faster under extended storage conditions, with their survival rates dropping significantly compared to X sperm after three days. Whether that translates into a meaningful advantage from timing intercourse in real-world conception, though, remains genuinely unclear.
Diet and Nutrition Claims
You’ll find advice suggesting that a diet higher in sodium and potassium increases the odds of having a boy. Animal research offers a sliver of support: hamsters fed diets supplemented with sodium and potassium produced male-to-female offspring at roughly a 2:1 ratio, compared to a 1:1 ratio in the control group. That’s a striking difference in hamsters, but animal studies frequently fail to translate to humans, and no well-designed human trial has confirmed the same effect.
Some proponents also suggest that higher caloric intake around conception is linked to male offspring, based on the biological logic that male fetuses are more metabolically demanding and more likely to survive when the mother’s energy availability is high. The evidence here is observational and weak. Changing your diet based on these findings is unlikely to cause harm, but there’s no reliable data suggesting it will meaningfully shift your odds from the baseline 51% chance of having a boy that exists naturally.
What the Baseline Odds Actually Look Like
Without any intervention, roughly 105 boys are born for every 100 girls worldwide. That means you already have a slight natural advantage if you’re hoping for a boy, about a 51.2% chance. Every natural method you’ll encounter online is attempting to push that number a few percentage points higher, and none has been proven to do so reliably in controlled human studies.
Deeper penetration during intercourse, female orgasm before male ejaculation, and specific sexual positions are all commonly recommended for conceiving a boy. These suggestions are extensions of the Shettles theory, the idea being that depositing sperm closer to the cervix or changing the pH environment gives Y sperm an edge. None of these recommendations have been tested in rigorous clinical research, and reproductive biologists generally consider them unproven.
Choosing Between Your Options
Your realistic choices fall into three tiers. IVF with PGT-A is the only method that approaches a guarantee, with 98% accuracy in identifying sex, but it’s expensive, physically demanding, and involves a full fertility treatment cycle. Sperm sorting offers a middle ground at around 81.5% accuracy for boys, with less physical burden, but limited clinic availability. Natural timing methods like Shettles are free and harmless to try, but the evidence is contradictory, and any effect on your odds is likely small.
If you’re already planning IVF for fertility reasons, adding PGT-A for sex selection is a relatively straightforward add-on. If you’re fertile and simply have a preference, the decision comes down to how much the outcome matters to you versus the cost, time, and physical toll of medical intervention. For most couples with a mild preference, trying natural timing methods costs nothing and carries no risk, even if the science behind them is uncertain.